Efforts to extend Moore's law for integrated circuitry (IC) have included development of transistors employing materials other than silicon, such as III-V compound semiconductor materials (e.g., InP, InGaAs, InAs). These high mobility material systems typically display higher carrier mobility than silicon devices, and so their introduction has long been suggested as path toward faster transistors. However, along with higher carrier mobility, in a field effect transistor (FET) the off-state (Ioff) leakage between source and drain can be significantly higher than for a silicon-based FET of equal effective (electrical) channel length. At high off-state drain to gate biases, band-to-band tunneling between the drain and gate insulator may cause Gate Induced Drain Leakage (GIDL) current. In a silicon-based FET, subthreshold leakage is typically much larger than GIDL current. However, with smaller band gap semiconductors in the gated channel, GIDL current can contribute significantly to Ioff.